Prepair 1000+

Gene: PEX1

Green List (high evidence)

Characterized clinically by severe neurologic dysfunction, craniofacial abnormalities, and liver dysfunction, and biochemically by the absence of peroxisomes. Most severely affected individuals with classic Zellweger syndrome phenotype die within the first year of life.
~98% of variants detectable by sequencing. The PEX1 variants c.2097_2098insT/p.Ile700YfsX42 and c.2528GRA/p.Gly843Asp are the most common.
Homozygosity for p.Ile700TyrfsTer42 is associated with a more severe phenotype. Homozygosity for p.Gly843Asp has to date been associated with a milder ZSD phenotype and sometimes with an intermediate phenotype.

Other phenotypes:
Peroxisome biogenesis disorder 1B (NALD/IRD), MIM #601539, characterised by overlapping phenotypes of neonatal adrenoleukodystrophy (NALD) and infantile Refsum disease (IRD), which represent the milder manifestations of the Zellweger syndrome spectrum. Many children presenting as newborns, whereas others do not come to attention until later. Many can communicate, and although language is rare, there have been children who have near normal language for age. Craniofacial anomalies are similar to but less pronounced than in Zellweger syndrome. In some individuals a leukodystrophy develops, with degeneration of myelin, loss of previously acquired skills, and development of spasticity; this may stabilize, or progress and be fatal. Associated with p.Gly843Asp variant? Should this phenotype be included for P1000?

Heimler syndrome-1 (MIM #234580) represents the mildest end of the peroxisomal biogenesis disorder spectrum, characterized by sensorineural hearing loss, enamel hypoplasia of the secondary dentition, and nail abnormalities. Not severe enough to report for P1000. See PMID: 26387595.

Created: 30 Dec 2024, 3:51 a.m. | Last Modified: 30 Dec 2024, 3:51 a.m.

Panel Version: 1.978

Mode of inheritance
BIALLELIC, autosomal or pseudoautosomal

Phenotypes
Peroxisome biogenesis disorder 1A (Zellweger), MIM #214100

Publications

• PMID: 20301621
• 9398847
• 17055079